【GT-安卓应用开发之评论列表实现】

前言：既然前面两篇文章记录了两种点赞列表的实现方式，那么这篇文章记录一下评论列表的实现吧。其实，评论列表的实现与第二种点赞列表的实现方式是相似的，都是利用自定义VIEW实现。不同的是点赞是自定义TextView，而这次的评论是自定义的线性布局（当然，自定义TextView也可以实现的）。这次评论列表采用自定义View继承LinearLayout，并动态添加TextView实现。

        

        正如上图所示，本篇文章记录一下这个简单demo的实现过程：

        第一步，自定义View

        创建Class-CommentView继承LinearLayout，并重写构造方法。与前面提到的点赞列表类似的，我们也是定义一个List和一个Context的属性，同样的定义一个bindData与notifyDataSetChanged方法。根据List的大小而动态添加TextView，TextView与前面的点赞是一样的都是利用ClickableSpan，StringBuilder等拼接字符串，代码如下：

public class CommentView extends LinearLayout{
    private Context mContext;
    private List<Comment> mDatas;
    public CommentView(Context context) {
        this(context, null);
    }

    public CommentView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CommentView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setOrientation(VERTICAL);
        this.mContext = context;
    }

    /**
     * 设置评论列表信息
     *
     * @param list
     */
    public void bindData(List<Comment> list) {
        mDatas = list;
    }



    public void notifyDataSetChanged() {
        removeAllViews();
        if (mDatas == null || mDatas.size() <= 0) {
            return;
        }
        LinearLayout.LayoutParams layoutParams = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
        layoutParams.setMargins(0, 10, 0, 10);
        for (int i = 0; i < mDatas.size(); i++) {
            View view = getView(i);
            if (view == null) {
                throw new NullPointerException("error");
            }
            addView(view, i, layoutParams);
        }
    }

    private View getView(final int position) {
        final Comment item = mDatas.get(position);
        boolean hasReply = false;   // 是否有回复
        if (item.getTag() != null) {
            if(!item.getTag().equals("false")) {
                hasReply = true;
            }
        }
        TextView textView = new TextView(mContext);
        textView.setTextSize(12);
        textView.setTextColor(0xff686868);
        String fromName = item.getFromName();
        String fromId = item.getFromId();
        String toName = item.getToName();
        String toId = item.getToId();
        SpannableStringBuilder builder = new SpannableStringBuilder();

        if (hasReply) {
            builder.append(setClickableSpan(fromName, item));
            builder.append(" 回复 ");
            builder.append(setClickableSpan(toName,item));

        } else {
            builder.append(setClickableSpan(fromName,item));
        }
        builder.append(" : ");
        builder.append(setClickableSpanContent(item.getContent(), item,position));
        builder.append(" ");
        textView.setText(builder);
        // 设置点击背景色
        textView.setHighlightColor(getResources().getColor(android.R.color.transparent));
        textView.setMovementMethod(LinkMovementMethod.getInstance());

        return textView;
    }

    /**
     * 设置评论内容点击事件
     *
     * @param item
     * @param bean
     * @param position
     * @return
     */
    public SpannableString setClickableSpanContent(final String item, final Comment bean,final int position) {
        final SpannableString string = new SpannableString(item);
        ClickableSpan span = new ClickableSpan() {
            @Override
            public void onClick(View widget) {
                //点击内容
                Toast.makeText(mContext,item,Toast.LENGTH_SHORT).show();
            }

            @Override
            public void updateDrawState(TextPaint ds) {
                super.updateDrawState(ds);
                // 设置显示的内容文本颜色
                ds.setColor(0xff686868);
                ds.setUnderlineText(false);
            }
        };
        string.setSpan(span, 0, string.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        return string;
    }

    /**
     * 设置评论用户名字点击事件
     *
     * @param item
     * @param bean
     * @return
     */
    public SpannableString setClickableSpan(final String item, final Comment bean) {
        final SpannableString string = new SpannableString(item);
        ClickableSpan span = new ClickableSpan() {
            @Override
            public void onClick(View widget) {
                //点击名字
                Toast.makeText(mContext,item,Toast.LENGTH_SHORT).show();
            }

            @Override
            public void updateDrawState(TextPaint ds) {
                super.updateDrawState(ds);
                // 设置显示的用户名文本颜色
                ds.setColor(Color.parseColor("#3CB371"));
                ds.setUnderlineText(false);
            }
        };

        string.setSpan(span, 0, string.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        return string;
    }


}

       第二步，在界面布局中定义CommentView

       第三步，数据绑定与界面渲染

lvPl = findViewById(R.id.lv_pl);
List<Comment> list = new ArrayList();
for(int i =0;i<10;i++){
    Comment com;
    if(i%2==0) {
        com = new Comment(i + "", "用户" + i, (i + 10) + "", "用户" + (i + 10),"测试回复" ,"true");
    }else{
        com = new Comment(i + "", "用户" + i, (i + 10) + "", "用户" + (i + 10),"测试评论" ,"false");
    }
    list.add(com);
}
lvPl.bindData(list);
lvPl.notifyDataSetChanged();

        注意：其实看起来与点赞列表的实现是相似的，只不过评论列表的实现逻辑比起点赞来稍微麻烦一点，因为它涉及到评论与回复是不一样的，我们在JavaBean中定义一个tag字段用于区分是评论还是回复。

public class Comment {
    private String content;
    private String fromId,toId;
    private String fromName,toName;
    private String tag;
    public Comment(String fromId,String fromName,String toId,String toName,String content){
        this.fromId = fromId;
        this.fromName = fromName;
        this.toId = toId;
        this.toName = toName;
        this.content = content;
        this.tag = "false";
    }
    public Comment(String fromId,String fromName,String toId,String toName,String content,String tag){
        this.fromId = fromId;
        this.fromName = fromName;
        this.toId = toId;
        this.toName = toName;
        this.content = content;
        this.tag = tag;
    }
    public String getTag() {
        return tag;
    }

    public void setContent(String content,String tag) {
        this.tag = tag;
    }
    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getFromId() {
        return fromId;
    }

    public void setFromId(String fromId) {
        this.fromId = fromId;
    }

    public String getToId() {
        return toId;
    }

    public void setToId(String toId) {
        this.toId = toId;
    }

    public String getFromName() {
        return fromName;
    }

    public void setFromName(String fromName) {
        this.fromName = fromName;
    }

    public String getToName() {
        return toName;
    }

    public void setToName(String toName) {
        this.toName = toName;
    }
}